This project seeks to elucidate critical mechanisms involved in regulating the development of tumoricidal function in macrophages obtained from different anatomical sites of cancer patients (pts). These goals are based on results which demonstrate impaired tumoricidal function in the macrophages from cancer pts following stimulation with conventional activators such as gamma interferon + endotoxin. tumoricidal function was found to vary both with the site from which the macrophages were obtained and the presence of malignant disease within the site. Thus, alveolar macrophages (AM) from lung cancer pts were significantly impaired in their tumoricidal function compared to the peripheral blood monocytes (PBM) from the same pts, or AM from control pts. Similar findings were obtained with peritoneal macrophages (PM) from ovarian cancer pts. Recently, however, we have developed a novel way to elicit tumoricidal function in tumor-associated macrophages which involves an initial cocultivation with allogeneic lymphocytes. We hypothesize that this results from either (i) the elicitation of cytokines distinct from those elicited by conventional activators and/or (ii) the activation of signaling pathways distinct from those normally used by macrophages to respond to conventional activators. Thus, the goal of the present proposal is to understand why conventional activators fail to elicit significant tumoricidal function in macrophages obtained from anatomical sites containing malignant disease, and why priming with allogeneic lymphocytes overcomes that deficiency. AM and PBM from pts with lung cancer and PM and PBM from pts with gynecological tumors will be studied. The role of specific monokines will be investigated focusing on the difference between monokines which may be produced versus monokines which are required for tumoricidal function. The approaches will include quantitative and kinetics studies of the monokines produced in response to different activation conditions, utilizing enzyme immunoassays and mRNA determinations as well as the use of specific anti- sense deoxyoligonucleotides to inhibit their synthesis. In addition, the ability of different activation conditions to stimulate specific signal transduction events will be investigated. The results obtained will be analyzed in light of studies which characterize macrophage populations phenotypically and histochemically to determine whether malignant disease influences definable aspects of macrophage heterogeneity. Finally, the specificity of these macrophage regulatory mechanisms for cancer pts will be assessed by comparing the results to those obtained in relevant disease-control populations.